Louis w



IlNTTsn STATES PATENT Grrrcn.

LOUIS XV. KIPP, OF HOBOKEN, NE\V JERSEY.

PROCESS OF ETCHING ZINC AND OTHER METAL PLATES.

SPECIFICATION forming part of Letters Patent No. 362,974. dated May 1'7, 1887.

Application filed Juncl7, 1886. Serial No. 205,454. (No specimens.)

To all whom, it may concern:

Be it known that I, LOUIS W. KIPP, a citizen ofthe United States, residing at Hobokcn, in the county of Hudson and State of New Jersey, have invented new and useful Improvements in Etching Zinc and other Metal Plates, of which the following is a specification.

In the art of etching figures or designs in metallic plates it is a common practice to transfer the designs upon the metallic plates from photographs, or to draw them thereon with an ink resisting the action ofthe acid employed in the etchingprocess,which eats away the surrounding metal, leaving the design in high relief. In following this method of etching, however,the edges of the design produced in relief become invariably rounded and the prints produced by means of such metallic printing-surfaces do not produce the desired effect.

The object of my invention is to produce in zinc and other metallic plates etched designs in relief with sharp edges or contours, and I will now proceed to describe minutely the process for etching which constitutes my invention.

I take a zinc plate having a smooth polished surface and draw thereon the required drawing or design with an ink composed of asphaltum, turpentine, and oil, (enough to keep the co1nposition in a liquid state,) and a little lampblack to darken it; or any engraving, be it either on stone, plate, wood, or any other material, can be transferred to the zinc plate by the common process, which is to take an impression from the engraving on paper (known as transfer-paper in the lithographic art) and transfer it to the zinc plate. The ink used by me for transferring is a composition of or dinary lithographic-printing ink with asphaltum in the proportion of about one-third of asphaltmu to two-thirds ofink. W'hen the drawing or transfer has been completed, and before the ink has become dry, I cover the same with a coat of powdered resin or copal, and the back of the plate is also covered with a coat of asphaltum or other acid-proof material in such a manner thatit is not affected by the acid used for etching.

After the zinc plate has been prepared in the manner above described I place the same in a bath of muriatic acid of about 1.2 specific gravity and let it remain about five seconds.

Then take it out, wash it, dry it, and when 5 dry heat it only enough to melt the powdered resin or copal, so as to form acrust which will protect the edges of the drawing or transfer which has been formed by the first exposure of the plate to the action of muriatic acid. I then return the plate to the bath of muriatic acid and again let it remain about five seconds, then wash and dry again. Then I cover those portions of the plate which are high enough to print with asphaltum and with another coat of powdered resin or copal,and place it again in the bath of muriatic acid and let it remain there until sufficient depth is obtained on the exposed parts of the plate. These operations of covering the plate and returning it to the bath may have to be repeated three or four times, according to the nature of the work.

My process is applicable to plates of all such metals which are attacked by innriatic acid in the same manner as zinc plates.

I do not restrict myself to muriatic acid, as other suitable acidssnch, for example, as nitric acid-may be usedin the process. The acids employed may be used in the pure state or diluted.

\Vhat I claim as ncw,and desire to secure by Letters Patent, is-- The within-described process for etching zinc and other metal plates, which consists in producing upon the surface of the plate the required design by means of an ink containing asphaltum, then covering the lines of the design with a powdered acid-proofsubstance, such as resin, theback of the plate being covered with an acid-proof substance, such as asphaltuin, then introducing the plate into a bath of muriatic or other suitable acid for a short time, then removing it from the bath, drying the same, and finally heating itto form a protecting crust on the edges of the design and then exposing it again to the bath, snbstantially as described.

In testimony whereof I have hereunto set my hand and seal in the presence of two subscribing witnesses.

LOUIS IV. KIPP. [L. s]

\Vitnesses:

W. HAUFF, E. F. KASTENHUBER. 

